Slide 1 of 32 Copyright Pearson Prentice Hall Biology

Slide 2 of 32 Copyright Pearson Prentice Hall 1-1 What is Science? 1.The goal of science is to: A. investigate B. understand the natural world. C. explain events in the natural world. D. use those explanations to make useful predictions.

1-2 How Scientists Work Slide 3 of 32 Copyright Pearson Prentice Hall Designing an Experiment 1-2 How Scientists work How do scientists test hypotheses? Whenever possible, a hypothesis should be tested by an experiment in which only one variable is changed at a time

1-2 How Scientists Work Slide 4 of 32 Copyright Pearson Prentice Hall Designing an Experiment 2. Designing an Experiment The process of testing a hypothesis includes: a. Asking a Question I wonder what the red fish will do in my hand?

1-2 How Scientists Work Slide 5 of 32 Copyright Pearson Prentice Hall Designing an Experiment b. Forming a Hypothesis a. Written as an If…..then…..statement (A prediction as to what is going to happen)

1-2 How Scientists Work Slide 6 of Supplies Needed: a. Red Fish Copyright Pearson Prentice Hall

1-2 How Scientists Work Slide 7 of 32 Copyright Pearson Prentice Hall Designing an Experiment 4. Setting Up a Controlled Experiment a. only 1 variable can be changed to be a valid experiment! b. manipulated variable : * variable that is deliberately changed c. responding variable: *is observed and changes in response to the manipulated variable

1-2 How Scientists Work Slide 8 of 32 Copyright Pearson Prentice Hall Thinking Like a Scientist 5. Observation: - process of gathering information in an orderly way. A. Involves using your senses!

1-2 How Scientists Work Slide 9 of 32 Copyright Pearson Prentice Hall Thinking Like a Scientist 6. Data: - information gathered from observations A. 2 types of data: 1. Quantitative data: * are expressed as numbers (obtained by counting or measuring) 2. Qualitative data: * descriptions * characteristics that can’t easily be measured.

1-2 How Scientists Work Slide 10 of 32 Copyright Pearson Prentice Hall Designing an Experiment 7. Drawing a Conclusion a. use the data from an experiment to evaluate a hypothesis and draw a valid conclusion. (Based on the data collected, my hypothesis was correct/incorrect because…….reference the data to explain)

1-2 How Scientists Work Slide 11 of 32 Copyright Pearson Prentice Hall Repeating Investigations 8. Repeating Investigations (repeat experiments to be sure that the results match those already obtained.)

Slide 12 of 32 Copyright Pearson Prentice Hall 1-2 How Scientists Work Spontaneous Generation: Life came from non-living things Maggots from meat Mice from grain Beetles on cow dung

1-2 How Scientists Work Slide 13 of 32 Copyright Pearson Prentice Hall Designing an Experiment Redi’s Experiment Controlled Variables: jars, type of meat, location, temperature, time Covered jars Uncovered jars

1-2 How Scientists Work Slide 14 of 32 Copyright Pearson Prentice Hall Designing an Experiment Redi’s Experiment Manipulated Variable: Gauze covering that keeps flies away from meat Responding Variable: whether maggots appear Maggots appear. Several days pass. No maggots appear.

1-2 How Scientists Work Slide 15 of 32 Copyright Pearson Prentice Hall Designing an Experiment Redi’s Experiment

1-2 How Scientists Work Slide 16 of 32 Copyright Pearson Prentice Hall Designing an Experiment Today, researchers use computers to record their work. Online storage makes it easier for researchers to review the data.

1-2 How Scientists Work Slide 17 of 32 Copyright Pearson Prentice Hall Repeating Investigations Needham's Test of Redi's Findings Needham challenged Redi’s results by claiming that spontaneous generation could occur under the right conditions. *

1-2 How Scientists Work Slide 18 of 32 Copyright Pearson Prentice Hall Repeating Investigations Needham’s Test of Redi’s Findings Needham sealed a bottle of gravy and heated it. After several days, the gravy was swarming with microorganisms. Needham concluded that these organisms came from the gravy by spontaneous generation.

1-2 How Scientists Work Slide 19 of 32 Copyright Pearson Prentice Hall Repeating Investigations Spallanzani's Test of Redi's Findings Gravy is boiled.

1-2 How Scientists Work Slide 20 of 32 Copyright Pearson Prentice Hall Repeating Investigations Spallanzani's Test of Redi's Findings Flask is open. Flask is sealed.

1-2 How Scientists Work Slide 21 of 32 Copyright Pearson Prentice Hall Repeating Investigations Spallanzani's Test of Redi's Findings Gravy is teeming with microorganisms. Gravy is free of microorganisms.

1-2 How Scientists Work Slide 22 of 32 Copyright Pearson Prentice Hall Repeating Investigations Pasteur's Test of Spontaneous Generation Louis Pasteur conclusively disproved the hypothesis of spontaneous generation. Pasteur showed that all living things come from other living things.

1-2 How Scientists Work Slide 23 of 32 Copyright Pearson Prentice Hall Repeating Investigations Pasteur’s Experiment Broth is boiled Broth is free of microorganisms for a year. Curved neck is removed. Broth is teeming with microorganisms.

1-2 How Scientists Work Slide 24 of 32 Copyright Pearson Prentice Hall Repeating Investigations The Impact of Pasteur’s Work Pasteur saved the French wine industry, which was troubled by unexplained souring of wine. He saved the silk industry, which was endangered by a silkworm disease. He began to uncover the nature of infectious diseases, showing that they were the result of microorganisms.

1-2 How Scientists Work Slide 25 of 32 Copyright Pearson Prentice Hall When Experiments Are Not Possible It is not always possible to do an experiment to test a hypothesis. For example: Wild animals must be observed without disturbing them. Ethical considerations prevent some experiments. By carefully planning alternative investigations, scientists can discover reliable patterns that add to scientific understanding.

1-2 How Scientists Work Slide 26 of 32 Copyright Pearson Prentice Hall How a Theory Develops How does a scientific theory develop?

1-2 How Scientists Work Slide 27 of 32 Copyright Pearson Prentice Hall How a Theory Develops As evidence from numerous investigations builds up, a hypothesis may become so well supported that scientists consider it a theory. In science, the word theory applies to a well-tested explanation that unifies a broad range of observations.

1-2 How Scientists Work Slide 28 of 32 Copyright Pearson Prentice Hall How a Theory Develops No theory is considered absolute truth. As new evidence is uncovered, a theory may be revised or replaced by a more useful explanation.

- or - Continue to: Click to Launch: Slide 29 of 32 Copyright Pearson Prentice Hall 1–2

Slide 30 of 32 Copyright Pearson Prentice Hall 1–2 In an experiment, the variable that is deliberately changed is called the a.control. b.manipulated variable. c.responding variable. d.constant control.

Slide 31 of 32 Copyright Pearson Prentice Hall 1–2 The mistaken belief that living organisms can arise from nonliving matter is called a.biogenesis. b.Pasteur's theory. c.spontaneous generation. d.Spallanzani’s hypothesis.

Slide 32 of 32 Copyright Pearson Prentice Hall 1–2 Which of the following was the manipulated variable in Redi’s experiment? a.the kind of meat used b.the temperature the jars were kept at c.the gauze covering on some jars d.the kind of fly that visited the jars

Slide 33 of 32 Copyright Pearson Prentice Hall 1–2 A well-tested explanation that unifies a broad range of observations is a a.hypothesis. b.variable. c.control. d.theory.

Slide 34 of 32 Copyright Pearson Prentice Hall 1–2 A scientific explanation does not become a theory until a.a majority of scientists agree with it. b.it has been supported by evidence from numerous investigations and observations. c.it is first proposed as an explanation. d.it is published in a textbook.

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